Technique for system initial program load or boot-up of electronic devices and systems

Abstract

A method, apparatus and program product for decreasing overall time for performing a system/device boot-up or initial program load (IPL). The system/device IPL code is organized into a plurality of portions, including a first portion and second portion. The first portion contains code to configure system memory, and is initially copied into the system's L2 cache. This first portion also provides initial control of cache inhibit and cache enable by way of software control. This first portion is executed from a non-volatile memory device to configure system memory and enable instruction caching by way of software control. The cache-enabling code is strategically located at a memory page boundary such that the system/device hardware will disable instruction prefetching in an adjoining page just past this cache enabling software code. After the system memory is configured by the initial portion of the IPL code, the second portion of the IPL code is copied into memory through the L2 cache and executed from memory with cache enabled to allow both normal and speculative instruction prefetching, thus improving overall system performance during system IPL.

Description

BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The present invention pertains to electronic devices and systems, and more particularly to an improved method and apparatus for starting up or booting an electronic device such as a data processing system. [0003] 2. Description of Related Art [0004] Many devices in use today include electronics that control the operation of at least some portion of the device. While data processing systems are the traditional types of systems that contain such electronics, electronic control is appearing in many other types of devices such as automobiles, telephones and other types of consumer electronics devices, and even home appliances. These types of devices typically have programming code stored within the device that gets executed when the device is initially turned-on or powered-up. This code, and its execution, may be called many different things, such as a boot-up, power-up, start-up or initial program load (IPL) of the device. So...

AI Technical Summary

Benefits of technology

[0013] The present invention provides an improved method, apparatus and program product for decreasing overall time for performing a system/device boot-up or initial program load (IPL) that occurs during system/device power-up or reset. The system/device IPL code or firmware is organized into a plurality of portions, including a first or initial portion and a second or remaining portion. The initial portion contains code to configure system memory, and initially copy itself into the system's L2 cache. This initial portion also provides initial control of cache inhibit and cache enable by way of software control. This initial portion is executed from a non-volatile memory device during the self-c

Problems solved by technology

Some types of systems, such as personal computers, are notoriously slow in providing a ready state after an initial power-up and IPL of the computer.

The reason for partially booting-up using flash memory programming and then transferring control to continue the boot-up sequence from main system memory is that flash memory is much more expensive than main system memory (which is typically comprised of DRAM memory), and therefore system designers want to use as little flash memory in their designs as possible to hold down on costs.

Obviously, the more functionality that is provided by the program stored in flash memory, the larger the size (and associated cost) of flash memory that will be required by the system/device.

Because CPUs/controllers have increased in operating speed at a much fa

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